1.
Acid
–
An acid is a molecule or ion capable of donating a hydron, or, alternatively, capable of forming a covalent bond with an electron pair. The first category of acids is the donors or Brønsted acids. In the special case of solutions, proton donors form the hydronium ion H3O+ and are known as Arrhenius acids. Brønsted and Lowry generalized the Arrhenius theory to include non-aqueous solvents, acids form aqueous solutions with a sour taste, can turn blue litmus red, and react with bases and certain metals to form salts. The word acid is derived from the Latin acidus/acēre meaning sour, an aqueous solution of an acid has a pH less than 7 and is colloquially also referred to as acid, while the strict definition refers only to the solute. A lower pH means a higher acidity, and thus a higher concentration of hydrogen ions in the solution. Chemicals or substances having the property of an acid are said to be acidic, common aqueous acids include hydrochloric acid, acetic acid, sulfuric acid, and citric acid. As these examples show, acids can be solutions or pure substances, strong acids and some concentrated weak acids are corrosive, but there are exceptions such as carboranes and boric acid. The second category of acids are Lewis acids, which form a covalent bond with an electron pair, however, hydrogen chloride, acetic acid, and most other Brønsted-Lowry acids cannot form a covalent bond with an electron pair and are therefore not Lewis acids. Conversely, many Lewis acids are not Arrhenius or Brønsted-Lowry acids, in modern terminology, an acid is implicitly a Brønsted acid and not a Lewis acid, since chemists almost always refer to a Lewis acid explicitly as a Lewis acid. Modern definitions are concerned with the chemical reactions common to all acids. Most acids encountered in life are aqueous solutions, or can be dissolved in water, so the Arrhenius. The Brønsted-Lowry definition is the most widely used definition, unless otherwise specified, hydronium ions are acids according to all three definitions. Interestingly, although alcohols and amines can be Brønsted-Lowry acids, they can function as Lewis bases due to the lone pairs of electrons on their oxygen and nitrogen atoms. The Swedish chemist Svante Arrhenius attributed the properties of acidity to hydrogen ions or protons in 1884, an Arrhenius acid is a substance that, when added to water, increases the concentration of H+ ions in the water. Thus, an Arrhenius acid can also be described as a substance that increases the concentration of ions when added to water. Examples include molecular substances such as HCl and acetic acid, an Arrhenius base, on the other hand, is a substance which increases the concentration of hydroxide ions when dissolved in water. Thus, an Arrhenius acid could also be said to be one that decreases hydroxide concentration, in an acidic solution, the concentration of hydronium ions is greater than 10−7 moles per liter
2.
Etching
–
Etching is traditionally the process of using strong acid or mordant to cut into the unprotected parts of a metal surface to create a design in intaglio in the metal. In modern manufacturing, other chemicals may be used on other types of material, as a method of printmaking, it is, along with engraving, the most important technique for old master prints, and remains in wide use today. In a number of variants such as microfabrication etching and photochemical milling it is a crucial technique in much modern technology. In traditional pure etching, a plate is covered with a waxy ground which is resistant to acid. The artist then scratches off the ground with an etching needle where he or she wants a line to appear in the finished piece. The échoppe, a tool with an oval section, is also used for swelling lines. The plate is dipped in a bath of acid, technically called the mordant or etchant. The acid bites into the metal where it is exposed, leaving behind lines sunk into the plate, the remaining ground is then cleaned off the plate. The plate is inked all over, and then the ink wiped off the surface, the plate is then put through a high-pressure printing press together with a sheet of paper. The paper picks up the ink from the lines, making a print. The process can be repeated many times, typically several hundred impressions could be printed before the shows much sign of wear. The work on the plate can also be added to by repeating the whole process, Etching has often been combined with other intaglio techniques such as engraving or aquatint. The process as applied to printmaking is believed to have been invented by Daniel Hopfer of Augsburg, Hopfer was a craftsman who decorated armour in this way, and applied the method to printmaking, using iron plates. Apart from his prints, there are two examples of his work on armour, a shield from 1536 now in the Real Armeria of Madrid. The switch to copper plates was made in Italy. On the other hand, the handling of the ground and acid need skill and experience, prior to 1100 AD, the New World Hohokam independently utilized the technique of acid etching in marine shell designs. Jacques Callot from Nancy in Lorraine made important technical advances in etching technique and he developed the échoppe, a type of etching-needle with a slanting oval section at the end, which enabled etchers to create a swelling line, as engravers were able to do. Callot also appears to have responsible for an improved, harder, recipe for the etching ground
3.
Carbon steel
–
The term carbon steel may also be used in reference to steel which is not stainless steel, in this use carbon steel may include alloy steels. As the carbon percentage content rises, steel has the ability to become harder and stronger through heat treating, however, regardless of the heat treatment, a higher carbon content reduces weldability. In carbon steels, the carbon content lowers the melting point. Mild steel, also known as steel and Low carbon steel. It is now the most common form of steel because its price is relatively low while it provides material properties that are acceptable for many applications, mild steel contains approximately 0. 05–0. 25% carbon making it malleable and ductile. Mild steel has a low tensile strength, but it is cheap and easy to form. It is often used large quantities of steel are needed. The density of steel is approximately 7.85 g/cm3. Low-carbon steels suffer from yield-point runout where the material has two yield points, the first yield point is higher than the second and the yield drops dramatically after the upper yield point. If a low-carbon steel is only stressed to some point between the upper and lower yield point then the surface develop Lüder bands, low-carbon steels contain less carbon than other steels and are easier to cold-form, making them easier to handle. Carbon steels which can successfully undergo heat-treatment have a content in the range of 0. 30–1. 70% by weight. Trace impurities of other elements can have a significant effect on the quality of the resulting steel. Trace amounts of sulfur in particular make the steel red-short, that is, brittle, low-alloy carbon steel, such as A36 grade, contains about 0. 05% sulfur and melts around 1, 426–1,538 °C. Manganese is often added to improve the hardenability of low-carbon steels and these additions turn the material into a low-alloy steel by some definitions, but AISIs definition of carbon steel allows up to 1. 65% manganese by weight. Carbon steel is broken down into four classes based on content,0.05 to 0. 25% carbon content. Balances ductility and strength and has good resistance, used for large parts, forging. Very strong, used for springs, swords, and high-strength wires, steels that can be tempered to great hardness. Used for special purposes like knives, axles or punches, most steels with more than 2. 5% carbon content are made using powder metallurgy
4.
Alloy steel
–
Alloy steel is steel that is alloyed with a variety of elements in total amounts between 1. 0% and 50% by weight to improve its mechanical properties. Alloy steels are broken down into two groups, low-alloy steels and high-alloy steels, the difference between the two is somewhat arbitrary, Smith and Hashemi define the difference at 4. 0%, while Degarmo, et al. define it at 8. 0%. Most commonly, the alloy steel refers to low-alloy steels. Strictly speaking, every steel is an alloy, but not all steels are called alloy steels, the simplest steels are iron alloyed with carbon. However, the alloy steel is the standard term referring to steels with other alloying elements added deliberately in addition to the carbon. Common alloyants include manganese, nickel, chromium, molybdenum, vanadium, silicon, less common alloyants include aluminum, cobalt, copper, cerium, niobium, titanium, tungsten, tin, zinc, lead, and zirconium. The following is a range of improved properties in alloy steels, strength, hardness, toughness, wear resistance, corrosion resistance, hardenability, to achieve some of these improved properties the metal may require heat treating. Some of these uses in exotic and highly-demanding applications, such as in the turbine blades of jet engines, in spacecraft. Because of the properties of iron, some steel alloys find important applications where their responses to magnetism are very important, including in electric motors. A few common low alloy steels are, D6AC 300M 256A Alloying elements are added to certain properties in the material. Manganese, silicon, or aluminum are added during the process to remove dissolved oxygen, sulfur. Manganese, silicon, nickel, and copper are added to increase strength by forming solid solutions in ferrite, chromium, vanadium, molybdenum, and tungsten increase strength by forming second-phase carbides. Nickel and copper improve corrosion resistance in small quantities, zirconium, cerium, and calcium increase toughness by controlling the shape of inclusions. Sulfur lead, bismuth, selenium, and tellurium increase machinability, the alloying elements tend to form either solid solutions or compounds or carbides. Nickel is very soluble in ferrite, therefore, it forms compounds, aluminium dissolves in the ferrite and forms the compounds Al2O3 and AlN. Silicon is also very soluble and usually forms the compound SiO2•MxOy, manganese mostly dissolves in ferrite forming the compounds MnS, MnO•SiO2, but will also form carbides in the form of 3C. Chromium forms partitions between the ferrite and carbide phases in steel, forming C, Cr7C3, and Cr23C6, the type of carbide that chromium forms depends on the amount of carbon and other types of alloying elements present. Tungsten and molybdenum form carbides if there is enough carbon and an absence of stronger carbide forming elements, they form the carbides W2C and Mo2C, vanadium, titanium, and niobium are strong carbide forming elements, forming vanadium carbide, titanium carbide, and niobium carbide, respectively
5.
Nickel
–
Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a golden tinge. Nickel belongs to the metals and is hard and ductile. Meteoric nickel is found in combination with iron, a reflection of the origin of elements as major end products of supernova nucleosynthesis. An iron–nickel mixture is thought to compose Earths inner core, use of nickel has been traced as far back as 3500 BCE. Nickel was first isolated and classified as an element in 1751 by Axel Fredrik Cronstedt. The elements name comes from a mischievous sprite of German miner mythology, Nickel, an economically important source of nickel is the iron ore limonite, which often contains 1–2% nickel. Nickels other important ore minerals include garnierite, and pentlandite, major production sites include the Sudbury region in Canada, New Caledonia in the Pacific, and Norilsk in Russia. Nickel is slowly oxidized by air at room temperature and is considered corrosion-resistant, historically, it has been used for plating iron and brass, coating chemistry equipment, and manufacturing certain alloys that retain a high silvery polish, such as German silver. About 6% of world production is still used for corrosion-resistant pure-nickel plating. Nickel-plated objects sometimes provoke nickel allergy, Nickel has been widely used in coins, though its rising price has led to some replacement with cheaper metals in recent years. Nickel is one of four elements that are ferromagnetic around room temperature, alnico permanent magnets based partly on nickel are of intermediate strength between iron-based permanent magnets and rare-earth magnets. The metal is valuable in modern times chiefly in alloys, about 60% of world production is used in nickel-steels, other common alloys and some new superalloys comprise most of the remainder of world nickel use, with chemical uses for nickel compounds consuming less than 3% of production. As a compound, nickel has a number of chemical manufacturing uses. Nickel is a nutrient for some microorganisms and plants that have enzymes with nickel as an active site. Nickel is a metal with a slight golden tinge that takes a high polish. It is one of four elements that are magnetic at or near room temperature. Its Curie temperature is 355 °C, meaning that bulk nickel is non-magnetic above this temperature, the unit cell of nickel is a face-centered cube with the lattice parameter of 0.352 nm, giving an atomic radius of 0.124 nm
6.
Sword
–
A sword is a long bladed weapon intended for slashing or thrusting. The precise definition of the term varies with the epoch or the geographical region under consideration. A sword consists of a blade attached to a hilt. The blade can be straight or curved, thrusting swords have a pointed tip on the blade, and tend to be straighter, slashing swords have sharpened cutting edge on one or both sides of the blade, and are more likely to be curved. Many swords are designed for thrusting and slashing. Historically, the sword developed in the Bronze Age, evolving from the dagger, the later Iron Age sword remained fairly short and without a crossguard. The word sword continues the Old English, sweord, the use of a sword is known as swordsmanship or as fencing. In the Early Modern period, western sword design diverged into two forms, the thrusting swords and the sabers. The thrusting swords such as the rapier and eventually the smallsword were designed to impale their targets quickly and their long and straight yet light and well balanced design made them highly maneuverable and deadly in a duel but fairly ineffective when used in a slashing or chopping motion. A well aimed lunge and thrust could end a fight in seconds with just the swords point, the saber and similar blades such as the cutlass were built more heavily and were more typically used in warfare. Built for slashing and chopping at multiple enemies, often from horseback, most sabers also had sharp points and double edged blades, making them capable of piercing soldier after soldier in a cavalry charge. Sabers continued to see use until the early 20th century. The US Navy kept tens of thousands of sturdy cutlasses in their armory well into World War II, non-European weapons called sword include single-edged weapons such as the Middle Eastern scimitar, the Chinese dao and the related Japanese katana. The Chinese jian is an example of a non-European double-edged sword, the first weapons that can be described as swords date to around 3300 BC. They have been found in Arslantepe, Turkey, are made from arsenical bronze, some of them are inlaid with silver. The sword developed from the dagger when the construction of longer blades became possible, from the late 3rd millennium BC in the Middle East, first in arsenic copper, then in tin-bronze. Blades longer than 60 cm were rare and not practical until the late Bronze Age because the strength of bronze is relatively low. These are the type A swords of the Aegean Bronze Age, one of the most important, and longest-lasting, types swords of the European Bronze Age was the Naue II type, also known as Griffzungenschwert
7.
Knife
–
A knife is a tool with a cutting edge or blade, hand-held or otherwise, with most having a handle. Some types of knives are used as utensils, including knives used at the dining table, many types of knives are used as tools, such as the utility knife carried by soldiers, the pocket knife carried by hikers and the hunting knife used by hunters. Knives are also used as a traditional or religious implement, such as the kirpan, some types of knives are used as weapons, such as daggers or switchblades. Some types of knives are used as sports equipment, Knives are also used in agriculture, food harvesting etc. the sickle, the scythe and even the combine harvester are knives. Knife-like tools were used at least two-and-a-half million years ago, as evidenced by the Oldowan tools. Originally made of rock, bone, flint, and obsidian, knives have evolved in construction as technology has, with blades being made from bronze, copper, iron, steel, ceramics, many cultures have their unique version of the knife. Due to its role as humankinds first tool, certain cultures have attached spiritual, most modern-day knives follow either a fixed-blade or a folding construction style, with blade patterns and styles as varied as their makers and countries of origin. The word knife possibly descends from an old Norse word knifr for blade, single-edged knives may have a reverse edge or false edge occupying a section of the spine. These edges are serrated and are used to further enhance function. The handle, used to grip and manipulate the blade safely, may include a tang, Knives are made with partial tangs or full tangs. The handle may include a bolster, a piece of heavy material situated at the front or rear of the handle, the bolster, as its name suggests, is used to mechanically strengthen the knife. Knife blades can be manufactured from a variety of materials, each of which has advantages and disadvantages, carbon steel, an alloy of iron and carbon, can be very sharp. It holds its edge well, and remains easy to sharpen, stainless steel is an alloy of iron, chromium, possibly nickel, and molybdenum, with only a small amount of carbon. It is not able to quite as sharp an edge as carbon steel. High carbon stainless steel is steel with a higher amount of carbon, intended to incorporate the better attributes of carbon steel. High carbon stainless steel blades do not discolor or stain, laminate blades use multiple metals to create a layered sandwich, combining the attributes of both. For example, a harder, more brittle steel may be sandwiched between a layer of softer, tougher, stainless steel to reduce vulnerability to corrosion. In this case, however, the part most affected by corrosion, pattern-welding is similar to laminate construction
8.
Metal
–
A metal is a material that is typically hard, opaque, shiny, and has good electrical and thermal conductivity. Metals are generally malleable—that is, they can be hammered or pressed permanently out of shape without breaking or cracking—as well as fusible and ductile, about 91 of the 118 elements in the periodic table are metals, the others are nonmetals or metalloids. Some elements appear in both metallic and non-metallic forms, astrophysicists use the term metal to collectively describe all elements other than hydrogen and helium, the simplest two, in a star. The star fuses smaller atoms, mostly hydrogen and helium, to larger ones over its lifetime. In that sense, the metallicity of an object is the proportion of its matter made up of all chemical elements. Many elements and compounds that are not normally classified as metals become metallic under high pressures, the atoms of metallic substances are typically arranged in one of three common crystal structures, namely body-centered cubic, face-centered cubic, and hexagonal close-packed. In bcc, each atom is positioned at the center of a cube of eight others, in fcc and hcp, each atom is surrounded by twelve others, but the stacking of the layers differs. Some metals adopt different structures depending on the temperature, atoms of metals readily lose their outer shell electrons, resulting in a free flowing cloud of electrons within their otherwise solid arrangement. This provides the ability of metallic substances to easily transmit heat, while this flow of electrons occurs, the solid characteristic of the metal is produced by electrostatic interactions between each atom and the electron cloud. This type of bond is called a metallic bond, Metals are usually inclined to form cations through electron loss, reacting with oxygen in the air to form oxides over various timescales. Examples,4 Na + O2 →2 Na2O2 Ca + O2 →2 CaO4 Al +3 O2 →2 Al2O3, the transition metals are slower to oxidize because they form a passivating layer of oxide that protects the interior. Others, like palladium, platinum and gold, do not react with the atmosphere at all, some metals form a barrier layer of oxide on their surface which cannot be penetrated by further oxygen molecules and thus retain their shiny appearance and good conductivity for many decades. The oxides of metals are generally basic, as opposed to those of nonmetals, exceptions are largely oxides with very high oxidation states such as CrO3, Mn2O7, and OsO4, which have strictly acidic reactions. Painting, anodizing or plating metals are good ways to prevent their corrosion, however, a more reactive metal in the electrochemical series must be chosen for coating, especially when chipping of the coating is expected. Water and the two form an electrochemical cell, and if the coating is less reactive than the coatee. Metals in general have high conductivity, high thermal conductivity. Typically they are malleable and ductile, deforming under stress without cleaving, in terms of optical properties, metals are shiny and lustrous. Sheets of metal beyond a few micrometres in thickness appear opaque, although most metals have higher densities than most nonmetals, there is wide variation in their densities, lithium being the least dense solid element and osmium the densest
9.
Damascus steel
–
Damascus steel was a type of steel used for manufacturing sword blades in the Near East made with wootz steel. These swords are characterized by patterns of banding and mottling reminiscent of flowing water. Such blades were reputed to be tough, resistant to shattering and capable of being honed to a sharp, the steel is named after Damascus, the capital city of Syria. It may either refer to swords made or sold in Damascus directly, or it may just refer to the aspect of the typical patterns, the original method of producing Damascus steel is not known. Modern attempts to duplicate the metal have not been successful due to differences in raw materials. Several individuals in modern times have claimed that they have rediscovered the methods by which the original Damascus steel was produced. The reputation and history of Damascus steel has given rise to many legends, a research team in Germany published a report in 2006 revealing nanowires and carbon nanotubes in a blade forged from Damascus steel. These ingots would then be further forged and worked into Damascus steel blades, research now shows that carbon nanotubes can be derived from plant fibers, suggesting how the nanotubes were formed in the steel. Some experts expect to discover such nanotubes in more relics as they are analyzed more closely, Damascus blades were manufactured in the Near East from ingots of wootz steel that were imported from India, as well as Sri Lanka. Archaeological evidence suggests that the steel process started in the present-day Tamil Nadu before the start of Common Era. The Arabs introduced the Indian wootz steel to Damascus, where a weapons industry thrived, from the 3rd century to the 17th century, India was shipping steel ingots to the Middle East. Production of these patterned swords gradually declined, ceasing by around 1750, the original Damascus steel or wootz was imported from India to Damascus, where bladesmiths learned how to forge them into swords. The technique for controlled thermal cycling after the initial forging at a specific temperature could also have been lost, recreating Damascus steel is a subfield of experimental archaeology. Many have attempted to discover or reverse-engineer the process by which it was made, pattern-welded steel has been referred to as Damascus steel since 1973 when Bladesmith William F. Moran unveiled his Damascus knives at the Knifemakers Guild Show. The patterns vary depending on how the works the billet. The billet is drawn out and folded until the number of layers are formed. In order to attain a Master Smith rating with the American Bladesmith Society that Moran founded, J. D. Verhoeven and A. H. Pendray published an article on their attempts to reproduce the elemental, structural, and visual characteristics of Damascus steel. The wootz was in a soft, annealed state, with a grain structure, however, Verhoeven and Pendray discovered that in samples of true Damascus steel, the Damascene pattern could be recovered by aging at a moderate temperature
10.
Forge
–
A forge is a type of hearth used for heating metals, or the workplace where such a hearth is located. The forge is used by the smith to heat a piece of metal to a temperature where it easier to shape by forging. The metal is transported to and from the forge using tongs, the slack tub also provides water to control the fire in the forge. A forge typically uses bituminous coal, industrial coke or charcoal as the fuel to heat metal, the designs of these forges have varied over time, but whether the fuel is coal, coke or charcoal the basic design has remained the same. The forge fire in this type of forge is controlled in three ways, amount of air, volume of fuel, and shape of the fuel/fire, traditionally hearths have been constructed of mud brick, fired brick, stone, or later, constructed of iron. During operation, fuel is placed in or on the hearth, a source of moving air, such as a fan or bellows, introduces additional air into the fire through the tuyere. With additional air, the fire more fuel and burns hotter (and cleaner - smoke can be thought of as escaped potential fuel. A blacksmith balances the fuel and air in the fire to suit particular kinds of work, often this involves adjusting and maintaining the shape of the fire. In a typical coal forge, a firepot will be centered in a flat hearth, the tuyere will enter the firepot at the bottom. In operation, the hot core of the fire will be a ball of burning coke in, the heart of the fire will be surrounded by a layer of hot but not burning coke. Around the unburnt coke will be a layer of coal being transformed into coke by the heat of the fire. If a larger fire is necessary, the smith increases the air flowing into the fire as well as feeding and deepening the coke heart, the smith can also adjust the length and width of the fire in such a forge to accommodate different shapes of work. The major variation from the forge and fire just described is a draft where there is no fire pot. Coke and charcoal may be burned in the forges that use coal, but since there is no need to convert the raw fuel at the heart of the fire. A gas forge typically uses propane or natural gas as the fuel, one common, efficient design uses a cylindrical forge chamber and a burner tube mounted at a right angle to the body. The chamber is lined with refractory materials such as a hard castable refractory ceramic or a soft ceramic thermal blanket. The burner mixes fuel and air which are ignited at the tip, the air pressure, and therefore heat, can be increased with a mechanical blower or by taking advantage of the Venturi effect. A small forge can even be carved out of a single soft firebrick, the primary advantage of a gas forge is ease of use, particularly for a novice
11.
Chemical milling
–
Chemical milling or industrial etching is the subtractive manufacturing process of using baths of temperature-regulated etching chemicals to remove material to create an object with the desired shape. It is mostly used on metals, though materials are increasingly important. It was developed from armor-decorating and printing etching processes developed during the Renaissance as alternatives to engraving on metal, most modern chemical milling methods involve alkaline etchants, these may have been used as early as the first century CE. Armor etching, using mineral acids, was not developed until the fifteenth century. Etchants mixed from salt, charcoal, and vinegar were applied to plate armor that had painted with a maskant of linseed-oil paint. The etchant would bite into the areas, causing the painted areas to be raised into relief. Not long after, it used to etch trajectory information plates for cannon and artillery operators, paper would rarely survive the rigors of combat. Often such information was etched onto equipment such as daggers or shovels. In 1782, the discovery was made by John Senebier that certain resins lost their solubility to turpentine when exposed to light, photo-chemical milling was extensively used in the development of photography methods, allowing light to create impressions on metal plates. Etching has applications in the circuit board and semiconductor fabrication industries. It is also used in the industry to remove shallow layers of material from large aircraft components, missile skin panels. Etching is used widely to manufacture integrated circuits and Microelectromechanical systems, in addition to the standard, liquid-based techniques, the semiconductor industry commonly uses plasma etching. Chemical milling is normally performed in a series of five steps, cleaning, masking, scribing, etching, cleaning is the preparatory process of ensuring that the surface to be etched is free of contaminants which could negatively impact the quality of the finished part. An improperly cleaned surface could result in poor adhesion of the maskant, causing areas to be etched erroneously, the surface must be kept free from oils, grease, primer coatings, markings and other residue from the marking out process, scale, and any other foreign contaminants. For most metals, this step can be performed by applying a solvent substance to the surface to be etched, the material may also be immersed in alkaline cleaners or specialized de-oxidizing solutions. It is common practice in modern industrial chemical etching facilities that the workpiece never be directly handled after this process, masking is the process of applying the maskant material to the surface to ensure that only desired areas are etched. Liquid maskants may be applied via dip-masking, in which the part is dipped into a tank of maskant. Maskant may also be applied by flow coating, liquid maskant is flowed over the surface of the part, certain conductive maskants may also be applied by electrostatic deposition, where electrical charges are applied to particles of maskant as it is sprayed onto the surface of the material
12.
Laminated steel blade
–
A laminated steel blade or piled steel is a knife, sword, or other tool blade made out of layers of differing types of steel, rather than a single homogeneous alloy. The earliest steel blades were laminated out of necessity, due to the bloomery method of smelting iron. Laminated steel offered both a way to average out the properties of the steel, as well as a way to high carbon steel to the areas that needed it most. Piled steel developed out of the complex process of making blades that were both hard and tough from the erratic and unsuitable output from early iron smelting in bloomeries. 06%. The bloom must then be heated and hammered to work out the impurities, Iron is too soft to make a good cutting edge, a good edge requires the addition of carbon to make steel. By heating thin iron rods in a forge, carbon could be added to the surface. From the beginning of the Iron Age, around 1200 BC, obtaining the right level of carbon was an art, and was very important to the finished product. The ideal sword is one with a hard, sharp edge, and tough enough to bend, blending a number of different pieces of iron and steel together averaged out the properties, ensuring that one bad piece would not produce a total failure of the finished product. This laminating different alloys together produces patterns that, with treatment, can be seen in the surface of the finished blade. Many swords were made with the minimum amount of high carbon steel along the cutting edge. A thin strip of high carbon steel could be laminated between two layers of steel, or a core of soft steel could be wrapped in high carbon steel. The Japanese katana was often found with complex patterns of soft and hard steels, the end result would be a blade with a very high carbon edge and a softer spine. The very hard, but brittle, edge made the extremely sharp, while the spine gave the blade flexibility. Many laminated steel blades, particularly those of the Vikings, also used complex structures of steel to produce patterns in the surface of the steel and these patterns were made by manipulating the piles, by twisting or otherwise distorting the piles, before they were forged into the blade. Modern laminated steel is still found in specialty knives and cutting tools, pattern welding is common in hand-made knives, where the primary goal is to provide a visually striking pattern in the final etched blade
13.
Carbon
–
Carbon is a chemical element with symbol C and atomic number 6. It is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds, three isotopes occur naturally, 12C and 13C being stable, while 14C is a radioactive isotope, decaying with a half-life of about 5,730 years. Carbon is one of the few elements known since antiquity, Carbon is the 15th most abundant element in the Earths crust, and the fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen. It is the second most abundant element in the body by mass after oxygen. The atoms of carbon can bond together in different ways, termed allotropes of carbon, the best known are graphite, diamond, and amorphous carbon. The physical properties of carbon vary widely with the allotropic form, for example, graphite is opaque and black while diamond is highly transparent. Graphite is soft enough to form a streak on paper, while diamond is the hardest naturally occurring material known, graphite is a good electrical conductor while diamond has a low electrical conductivity. Under normal conditions, diamond, carbon nanotubes, and graphene have the highest thermal conductivities of all known materials, all carbon allotropes are solids under normal conditions, with graphite being the most thermodynamically stable form. They are chemically resistant and require high temperature to react even with oxygen, the most common oxidation state of carbon in inorganic compounds is +4, while +2 is found in carbon monoxide and transition metal carbonyl complexes. The largest sources of carbon are limestones, dolomites and carbon dioxide, but significant quantities occur in organic deposits of coal, peat, oil. For this reason, carbon has often referred to as the king of the elements. The allotropes of carbon graphite, one of the softest known substances, and diamond. It bonds readily with other small atoms including other carbon atoms, Carbon is known to form almost ten million different compounds, a large majority of all chemical compounds. Carbon also has the highest sublimation point of all elements, although thermodynamically prone to oxidation, carbon resists oxidation more effectively than elements such as iron and copper that are weaker reducing agents at room temperature. Carbon is the element, with a ground-state electron configuration of 1s22s22p2. Its first four ionisation energies,1086.5,2352.6,4620.5 and 6222.7 kJ/mol, are higher than those of the heavier group 14 elements. Carbons covalent radii are normally taken as 77.2 pm,66.7 pm and 60.3 pm, although these may vary depending on coordination number, in general, covalent radius decreases with lower coordination number and higher bond order. Carbon compounds form the basis of all life on Earth
14.
Steelmaking
–
Steelmaking is the process for producing steel from iron ore and scrap. Limiting dissolved gases such as nitrogen and oxygen, and entrained impurities in the steel is also important to ensure the quality of the products cast from the liquid steel, steelmaking has existed for millennia, but it was not commercialized until the 19th century. The ancient craft process of steelmaking was the crucible process, in the 1850s and 1860s, the Bessemer process and the Siemens-Martin process turned steelmaking into a heavy industry. In recent times, EAF steelmaking technology has evolved closer to oxygen steelmaking as more energy is introduced into the process. Steelmaking has played a crucial role development of modern technological societies, cast iron is a hard brittle material that is difficult to work, whereas steel is malleable, relatively easily formed and a versatile material. For much of history, steel has only been made in small quantities. The earliest means of producing steel was in a bloomery, early modern methods of producing steel were often labour-intensive and highly skilled arts. See, finery forge, in which the German finery process could be managed to produce steel, an important aspect of the Industrial Revolution was the development of large-scale methods of producing forgeable metal. The puddling furnace was initially a means of producing wrought iron, the real revolution in steelmaking only began at the end of the 1850s when the Bessemer process became the first successful method of steelmaking in quantity, followed by the open-hearth furnace. Modern steelmaking processes can be broken into two categories, primary and secondary steelmaking, secondary steelmaking involves refining of the crude steel before casting and the various operations are normally carried out in ladles. Basic oxygen steelmaking is a method of steelmaking in which carbon-rich molten pig iron is made into steel. Blowing oxygen through molten pig iron lowers the carbon content of the alloy, the slag chemistry of the process is also controlled to ensure that impurities such as silicon and phosphorus are removed from the metal. The process was developed in 1948 by Robert Durrer and commercialized in 1952–53 by Austrian VOEST, the LD converter, named after the Austrian towns of Linz and Donawitz is a refined version of the Bessemer converter where blowing of air is replaced with blowing oxygen. It reduced capital cost of the plants, time of smelting, between 1920 and 2000, labour requirements in the industry decreased by a factor of 1,000, from more than 3 worker-hours per tonne to just 0.003. The vast majority of steel manufactured in the world is produced using the basic oxygen furnace, in 2011, it accounted for 70% of global steel output. Modern furnaces will take a charge of iron of up to 350 tons and convert it into steel in less than 40 minutes, electric arc furnace steelmaking is the manufacture of steel from scrap or direct reduced iron melted by electric arcs. In an electric arc furnace, a batch of steel may be started by loading scrap or direct reduced iron into the furnace, gas burners may be used to assist with the melt down of the scrap pile in the furnace. As in basic oxygen steelmaking, fluxes are also added to protect the lining of the vessel, electric arc furnace steelmaking typically uses furnaces of capacity around 100 tonnes that produce steel every 40 to 50 minutes for further processing
15.
Barong (knife)
–
The barong is a thick, leaf-shaped, single-edged blade sword. It is a used by Muslim Filipino ethnolinguistic groups like the Tausug. Barung blades are thick and very heavy with the weight aiding in the capability of the sword. Barong blade lengths range from 8 to 22 inches as the blade length is originally 14 inch. Newer blades, on the hand, tend to be longer measuring at 18 to 22 inches. Damascene patterns are also thick but again most often not as controlled as the widely known kalis. Most handles have a sleeve and lacquered braided fiber rings that sit on top. Nobility hilts were made of ivory, carabao horn, or kamagong, other barong swords have less elaborate hilts and are smaller in size. Common motifs include the cockatoo and naga, the long metal ferrule is most often made of silver, though copper, brass and swaasa is also used. Barongs used in World War II may also have aluminium ferrules, the ferrule tends to be around 8 cm in length. Often the ferrule will have lacquered braided fiber rings to aid in grip. Sometimes these fiber rings were on top of the ferrule, cockatoo pommels tended to be made of banati. Higher end barongs belonging to the classes often had large elaborately carved junggayan cockatoos. Barong for the classes, and the ones used for fighting, have less elaborate cockatoo pommels of much smaller sizes. At one period near World War II, cockatoo forms changed, crests became more triangular, and began to emerge directly from the back of the pommel, whereas older cockatoo had crests that flowed from the butt-plain of the pommel. Also, beaks started to more massive and rectangular in form. Barong used by juramentados, or those who had taken the rite of Magsabil, older barong scabbards tended only to be partially wrapped with large rattan lashings, while newer barong scabbards feature a full wrap of thin rattan. Also, the scabbards of older barong featured thinner flat boards, whereas post World War II barong scabbards are of much thicker stock, the terminus on modern-made scabbards tends to turn upward to a more dramatic degree, often at a near 90-degree angle and feature squared tips
16.
Hardness
–
Hardness is a measure of how resistant solid matter is to various kinds of permanent shape change when a compressive force is applied. Some materials are harder than others, Hardness is dependent on ductility, elastic stiffness, plasticity, strain, strength, toughness, viscoelasticity, and viscosity. Common examples of matter are ceramics, concrete, certain metals, and superhard materials. There are three types of hardness measurements, scratch, indentation, and rebound. Within each of these classes of measurement there are individual measurement scales, for practical reasons conversion tables are used to convert between one scale and another. Scratch hardness is the measure of how resistant a sample is to fracture or permanent plastic deformation due to friction from a sharp object, the principle is that an object made of a harder material will scratch an object made of a softer material. When testing coatings, scratch hardness refers to the necessary to cut through the film to the substrate. The most common test is Mohs scale, which is used in mineralogy, one tool to make this measurement is the sclerometer. Another tool used to make these tests is the pocket hardness tester and this tool consists of a scale arm with graduated markings attached to a four-wheeled carriage. A scratch tool with a rim is mounted at a predetermined angle to the testing surface. In order to use it a weight of mass is added to the scale arm at one of the graduated markings. The use of the weight and markings allows a known pressure to be applied without the need for complicated machinery. Indentation hardness measures the resistance of a sample to material deformation due to a constant compression load from an object, they are primarily used in engineering. The tests work on the premise of measuring the critical dimensions of an indentation left by a specifically dimensioned and loaded indenter. Common indentation hardness scales are Rockwell, Vickers, Shore, rebound hardness, also known as dynamic hardness, measures the height of the bounce of a diamond-tipped hammer dropped from a fixed height onto a material. This type of hardness is related to elasticity, the device used to take this measurement is known as a scleroscope. Two scales that measures rebound hardness are the Leeb rebound hardness test, there are five hardening processes, Hall-Petch strengthening, work hardening, solid solution strengthening, precipitation hardening, and martensitic transformation. Hardness in the elastic range—a small temporary change in shape for a given force—is known as stiffness in the case of a given object and they exhibit plasticity—the ability to permanently change shape in response to the force, but remain in one piece
17.
Bloomery
–
A bloomery is a type of furnace once widely used for smelting iron from its oxides. The bloomery was the earliest form of capable of smelting iron. A bloomerys product is a mass of iron and slag called a bloom. This mix of slag and iron in the bloom is termed sponge iron, the bloomery has now largely been superseded by the blast furnace, which produces pig iron. A bloomery consists of a pit or chimney with heat-resistant walls made of earth, clay, near the bottom, one or more pipes enter through the side walls. These pipes, called tuyères, allow air to enter the furnace, either by natural draught, an opening at the bottom of the bloomery may be used to remove the bloom, or the bloomery can be tipped over and the bloom removed from the top. The first step taken before the bloomery can be used is the preparation of the charcoal, the charcoal is produced by heating wood to produce the nearly pure carbon fuel needed for the smelting process. The ore is broken into pieces and usually roasted in a fire to remove any moisture in the ore. Any large impurities in the ore can be crushed and removed, since slag from previous blooms may have a high iron content, it can also be broken up and recycled into the bloomery with the new ore. In operation, the bloomery is preheated by burning charcoal, and once hot, iron ore and additional charcoal are introduced through the top, as the desired product of a bloomery is iron which is easily forgeable, it requires a low carbon content. The temperature and ratio of charcoal to iron ore must be controlled to keep the iron from absorbing too much carbon. Cast iron occurs when the iron melts and absorbs 2% to 4% carbon, because the bloomery is self-fluxing the addition of limestone is not required to form a slag. The mixed iron and slag cool to form a spongy mass referred to as the bloom. Because the bloom is highly porous, and its spaces are full of slag. Iron treated this way is said to be wrought, and the resulting iron and it is also possible to produce blooms coated in steel by manipulating the charge of and air flow to the bloomery. The onset of the Iron Age in most parts of the world coincides with the first widespread use of the bloomery, while earlier examples of iron are found, their high nickel content indicates that this is meteoric iron. Other early samples of iron may have produced by accidental introduction of iron ore in bronze smelting operations. Iron appears to have been smelted in the West as early as 3000 BC, in the West, iron began to be used around 1200 BC
18.
Redox
–
Redox is a chemical reaction in which the oxidation states of atoms are changed. Any such reaction involves both a process and a complementary oxidation process, two key concepts involved with electron transfer processes. Redox reactions include all chemical reactions in which atoms have their oxidation state changed, in general, the chemical species from which the electron is stripped is said to have been oxidized, while the chemical species to which the electron is added is said to have been reduced. It can be explained in terms, Oxidation is the loss of electrons or an increase in oxidation state by a molecule, atom. Reduction is the gain of electrons or a decrease in state by a molecule, atom. As an example, during the combustion of wood, oxygen from the air is reduced, the reaction can occur relatively slowly, as in the case of rust, or more quickly, as in the case of fire. Redox is a portmanteau of reduction and oxidation, the word oxidation originally implied reaction with oxygen to form an oxide, since dioxygen was historically the first recognized oxidizing agent. Later, the term was expanded to encompass oxygen-like substances that accomplished parallel chemical reactions, ultimately, the meaning was generalized to include all processes involving loss of electrons. The word reduction originally referred to the loss in weight upon heating a metallic ore such as an oxide to extract the metal. In other words, ore was reduced to metal, antoine Lavoisier showed that this loss of weight was due to the loss of oxygen as a gas. Later, scientists realized that the atom gains electrons in this process. The meaning of reduction then became generalized to all processes involving gain of electrons. Even though reduction seems counter-intuitive when speaking of the gain of electrons, it help to think of reduction as the loss of oxygen. Since electrons are charged, it is also helpful to think of this as reduction in electrical charge. The electrochemist John Bockris has used the words electronation and deelectronation to describe reduction and oxidation processes respectively when they occur at electrodes and these words are analogous to protonation and deprotonation, but they have not been widely adopted by chemists. The term hydrogenation could be used instead of reduction, since hydrogen is the agent in a large number of reactions. But, unlike oxidation, which has been generalized beyond its root element, the word redox was first used in 1928. The processes of oxidation and reduction occur simultaneously and cannot happen independently of one another, the oxidation alone and the reduction alone are each called a half-reaction, because two half-reactions always occur together to form a whole reaction
19.
Iron oxide
–
Iron oxides are chemical compounds composed of iron and oxygen. All together, there are sixteen known iron oxides and oxyhydroxides, common rust is a form of iron oxide. Iron oxides are used as inexpensive, durable pigments in paints, coatings. Colors commonly available are in the end of the yellow/orange/red/brown/black range. When used as a coloring, it has E number E172. Limonite Iron oxide nanoparticles List of inorganic pigments Information from Nano-Oxides, http, //chemed. chem. purdue. edu/demos/demosheets/12.3. html http, //minerals. usgs. gov/minerals/pubs/commodity/iron_oxide/ CDC - NIOSH Pocket Guide to Chemical Hazards de
20.
Ore
–
An ore is a type of rock that contains sufficient minerals with important elements including metals that can be economically extracted from the rock. The ores are extracted from the earth through mining, they are refined to extract the valuable element. The grade or concentration of an ore mineral, or metal, as well as its form of occurrence, will directly affect the costs associated with mining the ore. The cost of extraction must thus be weighed against the value contained in the rock to determine what ore can be processed. Metal ores are generally oxides, sulfides, silicates, or native metals that are not commonly concentrated in the Earths crust, the ores must be processed to extract the metals of interest from the waste rock and from the ore minerals. Ore bodies are formed by a variety of geological processes, the process of ore formation is called ore genesis. An ore deposit is an accumulation of ore and this is distinct from a mineral resource as defined by the mineral resource classification criteria. An ore deposit is one occurrence of a particular ore type, Ore deposits are classified according to various criteria developed via the study of economic geology, or ore genesis. Stratiform arkose-hosted and shale-hosted copper, typified by the Zambian copperbelt and this identifies, early on, whether further investment in estimation and engineering studies is warranted and identifies key risks and areas for further work. This is because the distribution of ores is unequal and dislocated from locations of peak demand. Other, lesser, commodities do not have international clearing houses and benchmark prices and this generally makes determining the price of ores of this nature opaque and difficult. Such metals include lithium, niobium-tantalum, bismuth, antimony and rare earths, most of these commodities are also dominated by one or two major suppliers with >60% of the worlds reserves. The London Metal Exchange aims to add uranium to its list of metals on warrant, the World Bank reports that China was the top importer of ores and metals in 2005 followed by the USA and Japan. Economic geology Mineral resource classification Ore genesis Petrology Froth Flotation Extractive metallurgy DILL, the “chessboard” classification scheme of mineral deposits, Mineralogy and geology from aluminum to zirconium, Earth-Science Reviews, Volume 100, Issue 1-4, June 2010, Pages 1-420
21.
Iron
–
Iron is a chemical element with symbol Fe and atomic number 26. It is a metal in the first transition series and it is by mass the most common element on Earth, forming much of Earths outer and inner core. It is the fourth most common element in the Earths crust, like the other group 8 elements, ruthenium and osmium, iron exists in a wide range of oxidation states, −2 to +6, although +2 and +3 are the most common. Elemental iron occurs in meteoroids and other low oxygen environments, but is reactive to oxygen, fresh iron surfaces appear lustrous silvery-gray, but oxidize in normal air to give hydrated iron oxides, commonly known as rust. Unlike the metals that form passivating oxide layers, iron oxides occupy more volume than the metal and thus flake off, Iron metal has been used since ancient times, although copper alloys, which have lower melting temperatures, were used even earlier in human history. Pure iron is soft, but is unobtainable by smelting because it is significantly hardened and strengthened by impurities, in particular carbon. A certain proportion of carbon steel, which may be up to 1000 times harder than pure iron. Crude iron metal is produced in blast furnaces, where ore is reduced by coke to pig iron, further refinement with oxygen reduces the carbon content to the correct proportion to make steel. Steels and iron alloys formed with metals are by far the most common industrial metals because they have a great range of desirable properties. Iron chemical compounds have many uses, Iron oxide mixed with aluminium powder can be ignited to create a thermite reaction, used in welding and purifying ores. Iron forms binary compounds with the halogens and the chalcogens, among its organometallic compounds is ferrocene, the first sandwich compound discovered. Iron plays an important role in biology, forming complexes with oxygen in hemoglobin and myoglobin. Iron is also the metal at the site of many important redox enzymes dealing with cellular respiration and oxidation and reduction in plants. A human male of average height has about 4 grams of iron in his body and this iron is distributed throughout the body in hemoglobin, tissues, muscles, bone marrow, blood proteins, enzymes, ferritin, hemosiderin, and transport in plasma. The mechanical properties of iron and its alloys can be evaluated using a variety of tests, including the Brinell test, Rockwell test, the data on iron is so consistent that it is often used to calibrate measurements or to compare tests. An increase in the content will cause a significant increase in the hardness. Maximum hardness of 65 Rc is achieved with a 0. 6% carbon content, because of the softness of iron, it is much easier to work with than its heavier congeners ruthenium and osmium. Because of its significance for planetary cores, the properties of iron at high pressures and temperatures have also been studied extensively
22.
Direct reduced iron
–
Direct-reduced iron, also called sponge iron, is produced from the direct reduction of iron ore to iron by a reducing gas or elementary carbon produced from natural gas or coal. Many ores are suitable for direct reduction, direct reduction refers to processes which reduce iron oxides to metallic iron at temperatures below the melting point of iron. The product of such solid state processes are called direct reduced iron, the reducing gas is a mixture of gases, primarily hydrogen and carbon monoxide. The process temperature is typically 800 to 1200 °C, direct reduction processes can be divided roughly into two categories, gas-based, and coal-based. In both cases, the objective of the process is to drive off the oxygen contained in various forms of iron ore, in order to convert the ore, without melting it, the direct reduction process is comparatively energy efficient. Steel made using DRI requires significantly less fuel, in that a traditional blast furnace is not needed, DRI is most commonly made into steel using electric arc furnaces to take advantage of the heat produced by the DRI product. In modern times, direct reduction processes have developed to specifically overcome the difficulties of conventional blast furnaces. DRI is successfully manufactured in various parts of the world, hot-briquetted iron is a compacted form of DRI designed for ease of shipping, handling, and storage. Hot direct reduced iron is not cooled before discharge from the reduction furnace. The direct reduction process uses pelletized iron ore or natural lump ore, one exception is the fluidized bed process which requires sized iron ore particles. The direct reduction process can use natural gas contaminated with inert gases, however, any inert gas contamination of the reducing gas lowers the effect of that gas stream and the thermal efficiency of the process. Supplies of powdered ore and raw natural gas are both available in such as Northern Australia, avoiding transport costs for the gas. In most cases the DRI plant is located near natural gas source as it is more cost effective to ship the ore rather than the gas and this method produces 97% pure iron. India is the world’s largest producer of direct-reduced iron, a constituent of the steel industry. Many other countries use variants of the process, so providing iron for local engineering industries, directly reduced iron is highly susceptible to oxidation and rusting if left unprotected, and is normally quickly processed further to steel. The bulk iron can also catch fire since it is pyrophoric, unlike blast furnace pig iron, which is almost pure metal, DRI contains some siliceous gangue, which needs to be removed in the steel-making process. Producing sponge iron and then working it was the earliest method used to iron in the Middle East, Egypt, and Europe. There is some evidence that the method was also used in China
23.
Carburizing
–
The intent is to make the metal harder. Depending on the amount of time and temperature, the area can vary in carbon content. Longer carburizing times and higher temperatures increase the depth of carbon diffusion.25 inches. In some cases it serves as a remedy for undesired decarburization that happened earlier in a manufacturing process, carburization of steel involves a heat treatment of the metallic surface using a source of carbon. Carburization can be used to increase the hardness of low carbon steel. Early carburization used an application of charcoal packed around the sample to be treated. For applications where control over gas composition is desired, carburization may take place under very low pressures in a vacuum chamber. Plasma carburization is increasingly used to improve the characteristics of various metals. It also provides a treatment of components with complex geometry. The process of carburization works via the diffusion of atoms into the surface layers of a metal. If the carbon remains in solution, the steel is then heat treated to harden it. Both of these mechanisms strengthen the surface of the metal, the former by forming pearlite or martensite, both of these materials are hard and resist abrasion. Gas carburizing is normally carried out at a temperature within the range of 900 to 950 °C, in oxy-acetylene welding, a carburizing flame is one with little oxygen, which produces a sooty, lower-temperature flame. It is often used to anneal metal, making it malleable and flexible during the welding process. A main goal when producing carburized workpieces is to ensure contact between the workpiece surface and the carbon-rich elements. In gas and liquid carburizing, the workpieces are often supported in mesh baskets or suspended by wire, in pack carburizing, the workpiece and carbon are enclosed in a container to ensure that contact is maintained over as much surface area as possible. Pack carburizing containers are made of carbon steel coated with aluminum or heat-resisting nickel-chromium alloy. There are different types of elements or materials that can be used to perform this process, a few typical hardening agents include carbon monoxide gas, sodium cyanide and barium carbonate, or hardwood charcoal
24.
Celts
–
The history of pre-Celtic Europe remains very uncertain. According to one theory, the root of the Celtic languages, the Proto-Celtic language, arose in the Late Bronze Age Urnfield culture of Central Europe. Thus this area is called the Celtic homeland. The earliest undisputed examples of a Celtic language are the Lepontic inscriptions beginning in the 6th century BC. Continental Celtic languages are attested almost exclusively through inscriptions and place-names, Insular Celtic languages are attested beginning around the 4th century in Ogham inscriptions, although it was clearly being spoken much earlier. Celtic literary tradition begins with Old Irish texts around the 8th century, coherent texts of Early Irish literature, such as the Táin Bó Cúailnge, survive in 12th century recensions. Between the 5th and 8th centuries, the Celtic-speaking communities in these Atlantic regions emerged as a cohesive cultural entity. They had a linguistic, religious and artistic heritage that distinguished them from the culture of the surrounding polities. By the 6th century, however, the Continental Celtic languages were no longer in wide use, Insular Celtic culture diversified into that of the Gaels and the Celtic Britons of the medieval and modern periods. A modern Celtic identity was constructed as part of the Romanticist Celtic Revival in Great Britain, Ireland, today, Irish, Scottish Gaelic, Welsh, and Breton are still spoken in parts of their historical territories, and Cornish and Manx are undergoing a revival. The first recorded use of the name of Celts – as Κελτοί – to refer to a group was by Hecataeus of Miletus, the Greek geographer, in 517 BC. In the fifth century BC Herodotus referred to Keltoi living around the head of the Danube, the etymology of the term Keltoi is unclear. Possible roots include Indo-European *kʲel ‘to hide’, IE *kʲel ‘to heat’ or *kel ‘to impel’, several authors have supposed it to be Celtic in origin, while others view it as a name coined by Greeks. Linguist Patrizia De Bernardo Stempel falls in the group. Yet he reports Celtic peoples in Iberia, and also uses the ethnic names Celtiberi and Celtici for peoples there, as distinct from Lusitani, pliny the Elder cited the use of Celtici in Lusitania as a tribal surname, which epigraphic findings have confirmed. Latin Gallus might stem from a Celtic ethnic or tribal name originally and its root may be the Proto-Celtic *galno, meaning “power, strength”, hence Old Irish gal “boldness, ferocity” and Welsh gallu “to be able, power”. The tribal names of Gallaeci and the Greek Γαλάται most probably have the same origin, the suffix -atai might be an Ancient Greek inflection. Proto-Germanic *walha is derived ultimately from the name of the Volcae and this means that English Gaul, despite its superficial similarity, is not actually derived from Latin Gallia, though it does refer to the same ancient region
25.
Ulfberht swords
–
The Ulfberht swords are about 170 medieval swords found in Europe, dated to the 9th to 11th centuries, with blades inlaid with the inscription +VLFBERHT+. That word is a Frankish personal name became the basis of a trademark of sorts. The swords are at the point between the Viking sword and the high medieval knightly sword. Most have blades of Oakeshott type X and they are also the starting point of the high medieval tradition of blade inscriptions. The reverse side of the blades are inlaid with a geometric pattern, there are also numerous blades which have this type of geometric pattern but no Vlfberht inscription. The group of Ulfberht swords includes a spectrum of steel. One example from a 10th-century grave in Nemilany, Moravia, has a pattern welded core with welded-on hardened cutting edges, another example appears to have been made from high-quality hypoeutectoid steel possibly imported from Central Asia. The first systematic study of type of sword is the one by Lorange. The original Ulfberht sword type dates to the 9th or 10th century, Ulfberht swords are found throughout Europe, most numerously in Northern Europe. They most likely originate in the Rhineland region of Germany, but were clearly sought-after, three specimens were found as far afield as Volga Bulgaria. g. in riverbeds. In 2012, after the publication of the survey by Stralsberg, there are about 170 extant Ulfberht blades. Of 166 candidate blades, Stalsberg classifies 96 as clearly featuring an Vlfberht inscription, or 135 including non definable or uncertain variants, about a quarter from Norway alone. The precise number is debatable because of the condition of some examples. Stalsberg is based on a survey of 166 blades, the inscription typology in Stalsberg is limited to a total of 135 blades, Viking Age arms and armour Ingelrii, a similar inscription Anders Lorange, Den yngre jernalders sværd, Bergen. Rudolf Wegeli, Inschriften auf mittelalterlichen Schwertklingen, Leipzig, anne Stalsberg, Herstellung und Verbreitung der Vlfberht-Schwertklingen. Eine Neubewertung, Zeitschrift für Archäologie des Mittelalters 36,2008, M. Müller-Wille, Ein neues ULFBERHT-Schwert aus Hamburg. Verbreitung, Formenkunde und Herkunft, Offa 27,1970, 65-91 Media related to Ulfberht swords at Wikimedia Commons
26.
Viking era
–
The Viking Age is the period from the late 8th century to the mid-11th century in European history, especially Northern European and Scandinavian history, following the Germanic Iron Age. It is the period of history when Scandinavian Norsemen explored Europe by its seas and rivers for trade, raids, colonisation and conquest. Three Viking ships had beached in Weymouth Bay four years earlier, the Viking devastation of Northumbrias Holy Island was reported by the Northumbrian scholar Alcuin of York, who wrote, Never before in Britain has such a terror appeared. Vikings were portrayed as violent and bloodthirsty by their enemies. The chronicles of medieval England portrayed them as rapacious wolves among sheep, the first challenges to the many anti-Viking images in Britain emerged in the 17th century. Pioneering scholarly works on the Viking Age reached a readership in Britain. Archaeologists began to dig up Britains Viking past, linguistics traced the Viking-Age origins of rural idioms and proverbs. New dictionaries of the Old Norse language enabled more Victorians to read the Icelandic Sagas, the Vikings who invaded western and eastern Europe were chiefly pagans from Denmark, Norway and Sweden. They also settled in the Faroe Islands, Ireland, Iceland, peripheral Scotland, Greenland and their North Germanic language, Old Norse, became the mother-tongue of present-day Scandinavian languages. By 801, a central authority appears to have been established in Jutland. In Norway, mountainous terrain and fjords formed strong natural boundaries, communities there remained independent of each other, unlike the situation in Denmark which is lowland. By 800, some 30 small kingdoms existed in Norway, the sea was the easiest way of communication between the Norwegian kingdoms and the outside world. It was in the 8th century that Scandinavians began to build ships of war, the North Sea rovers were traders, colonisers and explorers as well as plunderers. There are various theories concerning the causes of the Viking invasions, for people living along the coast, it would seem natural to seek new land by the sea. Another reason was that during this period England, Wales and Ireland, the Franks, however, had well-defended coasts and heavily fortified ports and harbours. Pure thirst for adventure may also have been a factor, a reason for the raids is believed by some to be over-population caused by technological advances, such as the use of iron, or a shortage of women due to selective female infanticide. Although another cause could well have been caused by the Frankish expansion to the south of Scandinavia. Consequently, these Vikings became raiders, in search of subsistence, There is ongoing debate among scholars as to why the Scandinavians began to expand during the 8th through 11th centuries
27.
Middle Ages
–
In the history of Europe, the Middle Ages or Medieval Period lasted from the 5th to the 15th century. It began with the fall of the Western Roman Empire and merged into the Renaissance, the Middle Ages is the middle period of the three traditional divisions of Western history, classical antiquity, the medieval period, and the modern period. The medieval period is subdivided into the Early, High. Population decline, counterurbanisation, invasion, and movement of peoples, the large-scale movements of the Migration Period, including various Germanic peoples, formed new kingdoms in what remained of the Western Roman Empire. In the seventh century, North Africa and the Middle East—once part of the Byzantine Empire—came under the rule of the Umayyad Caliphate, although there were substantial changes in society and political structures, the break with classical antiquity was not complete. The still-sizeable Byzantine Empire survived in the east and remained a major power, the empires law code, the Corpus Juris Civilis or Code of Justinian, was rediscovered in Northern Italy in 1070 and became widely admired later in the Middle Ages. In the West, most kingdoms incorporated the few extant Roman institutions, monasteries were founded as campaigns to Christianise pagan Europe continued. The Franks, under the Carolingian dynasty, briefly established the Carolingian Empire during the later 8th, the Crusades, first preached in 1095, were military attempts by Western European Christians to regain control of the Holy Land from Muslims. Kings became the heads of centralised nation states, reducing crime and violence, intellectual life was marked by scholasticism, a philosophy that emphasised joining faith to reason, and by the founding of universities. Controversy, heresy, and the Western Schism within the Catholic Church paralleled the conflict, civil strife. Cultural and technological developments transformed European society, concluding the Late Middle Ages, the Middle Ages is one of the three major periods in the most enduring scheme for analysing European history, classical civilisation, or Antiquity, the Middle Ages, and the Modern Period. Medieval writers divided history into periods such as the Six Ages or the Four Empires, when referring to their own times, they spoke of them as being modern. In the 1330s, the humanist and poet Petrarch referred to pre-Christian times as antiqua, leonardo Bruni was the first historian to use tripartite periodisation in his History of the Florentine People. Bruni and later argued that Italy had recovered since Petrarchs time. The Middle Ages first appears in Latin in 1469 as media tempestas or middle season, in early usage, there were many variants, including medium aevum, or middle age, first recorded in 1604, and media saecula, or middle ages, first recorded in 1625. The alternative term medieval derives from medium aevum, tripartite periodisation became standard after the German 17th-century historian Christoph Cellarius divided history into three periods, Ancient, Medieval, and Modern. The most commonly given starting point for the Middle Ages is 476, for Europe as a whole,1500 is often considered to be the end of the Middle Ages, but there is no universally agreed upon end date. English historians often use the Battle of Bosworth Field in 1485 to mark the end of the period
28.
India
–
India, officially the Republic of India, is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and it is bounded by the Indian Ocean on the south, the Arabian Sea on the southwest, and the Bay of Bengal on the southeast. It shares land borders with Pakistan to the west, China, Nepal, and Bhutan to the northeast, in the Indian Ocean, India is in the vicinity of Sri Lanka and the Maldives. Indias Andaman and Nicobar Islands share a border with Thailand. The Indian subcontinent was home to the urban Indus Valley Civilisation of the 3rd millennium BCE, in the following millennium, the oldest scriptures associated with Hinduism began to be composed. Social stratification, based on caste, emerged in the first millennium BCE, early political consolidations took place under the Maurya and Gupta empires, the later peninsular Middle Kingdoms influenced cultures as far as southeast Asia. In the medieval era, Judaism, Zoroastrianism, Christianity, and Islam arrived, much of the north fell to the Delhi sultanate, the south was united under the Vijayanagara Empire. The economy expanded in the 17th century in the Mughal empire, in the mid-18th century, the subcontinent came under British East India Company rule, and in the mid-19th under British crown rule. A nationalist movement emerged in the late 19th century, which later, under Mahatma Gandhi, was noted for nonviolent resistance, in 2015, the Indian economy was the worlds seventh largest by nominal GDP and third largest by purchasing power parity. Following market-based economic reforms in 1991, India became one of the major economies and is considered a newly industrialised country. However, it continues to face the challenges of poverty, corruption, malnutrition, a nuclear weapons state and regional power, it has the third largest standing army in the world and ranks sixth in military expenditure among nations. India is a constitutional republic governed under a parliamentary system. It is a pluralistic, multilingual and multi-ethnic society and is home to a diversity of wildlife in a variety of protected habitats. The name India is derived from Indus, which originates from the Old Persian word Hindu, the latter term stems from the Sanskrit word Sindhu, which was the historical local appellation for the Indus River. The ancient Greeks referred to the Indians as Indoi, which translates as The people of the Indus, the geographical term Bharat, which is recognised by the Constitution of India as an official name for the country, is used by many Indian languages in its variations. Scholars believe it to be named after the Vedic tribe of Bharatas in the second millennium B. C. E and it is also traditionally associated with the rule of the legendary emperor Bharata. Gaṇarājya is the Sanskrit/Hindi term for republic dating back to the ancient times, hindustan is a Persian name for India dating back to the 3rd century B. C. E. It was introduced into India by the Mughals and widely used since then and its meaning varied, referring to a region that encompassed northern India and Pakistan or India in its entirety
29.
Scandinavia
–
Scandinavia /ˌskændᵻˈneɪviə/ is a historical and cultural region in Northern Europe characterized by a common ethnocultural North Germanic heritage and mutually intelligible North Germanic languages. The term Scandinavia always includes the three kingdoms of Denmark, Norway and Sweden, the remote Norwegian islands of Svalbard and Jan Mayen are usually not seen as a part of Scandinavia, nor is Greenland, an overseas territory of Denmark. This looser definition almost equates to that of the Nordic countries, in Nordic languages, only Denmark, Norway and Sweden are commonly included in the definition of Scandinavia. In English usage, Scandinavia sometimes refers to the geographical area, the name Scandinavia originally referred vaguely to the formerly Danish, now Swedish, region Scania. Icelanders and the Faroese are to a significant extent descended from the Norse, Finland is mainly populated by Finns, with a minority of approximately 5% of Swedish speakers. A small minority of Sami people live in the north of Scandinavia. The Danish, Norwegian and Swedish languages form a continuum and are known as the Scandinavian languages—all of which are considered mutually intelligible with one another. Faroese and Icelandic, sometimes referred to as insular Scandinavian languages, are intelligible in continental Scandinavian languages only to a limited extent, Finnish and Meänkieli are closely related to each other and more distantly to the Sami languages, but are entirely unrelated to the Scandinavian languages. Apart from these, German, Yiddish and Romani are recognized minority languages in Scandinavia, the southern and by far most populous regions of Scandinavia have a temperate climate. Scandinavia extends north of the Arctic Circle, but has mild weather for its latitude due to the Gulf Stream. Much of the Scandinavian mountains have a tundra climate. There are many lakes and moraines, legacies of the last glacial period, Scandinavia usually refers to Denmark, Norway, and Sweden. Some sources argue for the inclusion of the Faroe Islands, Finland and Iceland, though that broader region is known by the countries concerned as Norden. Before this time, the term Scandinavia was familiar mainly to classical scholars through Pliny the Elders writings, and was used vaguely for Scania, as a political term, Scandinavia was first used by students agitating for Pan-Scandinavianism in the 1830s. After a visit to Sweden, Andersen became a supporter of early political Scandinavism, the term is often defined according to the conventions of the cultures that lay claim to the term in their own use. More precisely, and subject to no dispute, is that Finland is included in the broader term Nordic countries, various promotional agencies of the Nordic countries in the United States serve to promote market and tourism interests in the region. The official tourist boards of Scandinavia sometimes cooperate under one umbrella, Norways government entered one year later. All five Nordic governments participate in the joint promotional efforts in the United States through the Scandinavian Tourist Board of North America, Scandinavia can thus be considered a subset of the Nordic countries
30.
Mora knife
–
A mora knife is a range of small sheath knife similar in design to the Finnish puukko. Other famous great Old World knives are Opinels, a French folding knife, Eka, a Swedish folding knife, Germanys Mercator folding knives, and the Swiss Army Knife by Victorinox. The Morakniv company uses blades of 12C27 stainless steel, UHB-20C carbon steel, Triflex steel, other manufacturers of mora-type knives are Cocraft a house brand of Clas Ohlson, Best Tools and Hultafors. Morakniv, sedan 1891, från begrepp till varumärke
31.
Crucible steel
–
Crucible steel is a term that applies to steel made by two different methods in the modern era, although it has been produced in varying locales throughout history. It is made by melting iron and other materials in a crucible, Crucible steel was produced in South and Central Asia during the medieval era. The homogeneous crystal structure of this cast steel improved its strength, only recently it has become apparent that places in Central Asia like Merv in Turkmenistan and Akhsiket in Uzbekistan were important centres of production of crucible steel. The Central Asian finds are all from excavations and date from the 8th to 12th centuries AD, while crucible steel is more attributed to the Middle East in early times, there have been swords discovered in Europe, particularly in Scandinavia. The swords in question have the ambiguous name inlaid into it and these swords actually date to a 200-year period from the 9th century to the early 11th century. It is speculated by many that the process of making the blades originated in the Middle East, in the first centuries of the Islamic period, there appear some scientific studies on swords and steel. The best known of these are by Jabir ibn Hayyan 8th century, al-Kindi 9th century, Al-Biruni in the early 11th century, al-Tarsusi in the late 12th century, and Fakhr-i-Mudabbir 13th century. Any of these far more information about Indian and damascene steels than appears in the entire surviving literature of classical Greece. Indian/Sri Lankan crucible steel is commonly referred to as wootz, which is agreed to be an English corruption of the word ukko or hookoo. As yet the scale of excavations and surface surveys is too limited to link the literary accounts to archaeometallurgical evidence. The known sites of crucible steel production in south India, i. e. at Konasamudram and Gatihosahalli, date from at least the medieval period. One of the earliest known sites, which shows some promising evidence that may be linked to ferrous crucible processes in Kodumanal. The site is dated between the third century BC and the third century AD, by the seventeenth century the main centre of crucible steel production seems to have been in Hyderabad. The process was quite different from that recorded elsewhere. Wootz from Hyderabad or the Decanni process for making watered blades involved a co-fusion of two different kinds of iron, one was low in carbon and the other was a steel or cast iron. Wootz steel was exported and traded throughout ancient Europe, China, the Arab world, and became particularly famous in the Middle East. Recent archaeological investigations have suggested that Sri Lanka also supported innovative technologies for iron, the Sri Lankan system of crucible steel making was partially independent of the various Indian and Middle Eastern systems. Their method was something similar to the method of carburization of wrought iron, the earliest confirmed crucible steel site is located in the knuckles range in the northern area of the Central Highlands of Sri Lanka dated to 6th −10th centuries AD
32.
Tool steel
–
Tool steel refers to a variety of carbon and alloy steels that are particularly well-suited to be made into tools. Their suitability comes from their distinctive hardness, resistance to abrasion and deformation, as a result, tool steels are suited for their use in the shaping of other materials. With a carbon content between 0. 5% and 1. 5%, tool steels are manufactured under controlled conditions to produce the required quality. The presence of carbides in their plays the dominant role in the qualities of tool steel. The four major alloying elements in tool steel that form carbides are, tungsten, the rate of dissolution of the different carbides into the austenite form of the iron determines the high temperature performance of steel. Proper heat treatment of these steels is important for adequate performance, the manganese content is often kept low to minimize the possibility of cracking during water quenching. There are six groups of tool steels, water-hardening, cold-work, shock-resistant, high-speed, hot-work, the choice of group to select depends on cost, working temperature, required surface hardness, strength, shock resistance, and toughness requirements. The more severe the service condition, the higher the content and consequent amount of carbides required for the tool steel. Tool steels are used for cutting, pressing, extruding, and coining of metals, the AISI-SAE grades of tool steel is the most common scale used to identify various grades of tool steel. Individual alloys within a grade are given a number, for example, A2, O1, W-group tool steel gets its name from its defining property of having to be water quenched. W-grade steel is essentially high carbon plain-carbon steel and this group of tool steel is the most commonly used tool steel because of its low cost compared to others. They work well for parts and applications where high temperatures are not encountered. Its hardenability is low, so W-group tool steels must be subjected to a rapid quenching, requiring the use of water and these steels can attain high hardness and are rather brittle compared to other tool steels. W-steels are still sold, especially for springs, but are less widely used than they were in the 19th. This is partly because W-steels warp and crack much more during quench than oil-quenched or air hardening steels, the toughness of W-group tool steels are increased by alloying with manganese, silicon and molybdenum. Up to 0. 20% of vanadium is used to fine grain sizes during heat treating. 0. 76–0. 90% carbon, forging dies, hammers,0. 91–1. 10% carbon, general purpose tooling applications that require a good balance of wear resistance and toughness, such as rasps, drills, cutters, and shear blades. 1. 11–1. 30% carbon, files, small drills, lathe tools, razor blades, and other light-duty applications where more wear resistance is required without great toughness
33.
Stainless steel
–
In metallurgy, stainless steel, also known as inox steel or inox from French inoxydable, is a steel alloy with a minimum of 10. 5% chromium content by mass. Stainless steel is notable for its resistance, and it is widely used for food handling. Stainless steel does not readily corrode, rust or stain with water as ordinary steel does, however, it is not fully stain-proof in low-oxygen, high-salinity, or poor air-circulation environments. There are various grades and surface finishes of stainless steel to suit the environment the alloy must endure, Stainless steel is used where both the properties of steel and corrosion resistance are required. Stainless steel differs from carbon steel by the amount of chromium present, unprotected carbon steel rusts readily when exposed to air and moisture. This iron oxide film is active and accelerates corrosion by making it easier for more iron oxide to form, since iron oxide has lower density than steel, the film expands and tends to flake and fall away. In comparison, stainless steels contain sufficient chromium to undergo passivation and this layer prevents further corrosion by blocking oxygen diffusion to the steel surface and stops corrosion from spreading into the bulk of the metal. Passivation occurs only if the proportion of chromium is high enough, Stainless steel’s resistance to corrosion and staining, low maintenance, and familiar lustre make it an ideal material for many applications. Storage tanks and tankers used to transport orange juice and other food are made of stainless steel. This also influences its use in kitchens and food processing plants, as it can be steam-cleaned and sterilized. High oxidation resistance in air at ambient temperature is achieved with addition of a minimum of 13% chromium. The chromium forms a layer of chromium oxide when exposed to oxygen. The layer is too thin to be visible, and the metal remains lustrous, the layer is impervious to water and air, protecting the metal beneath, and this layer quickly reforms when the surface is scratched. This phenomenon is called passivation and is seen in other metals, corrosion resistance can be adversely affected if the component is used in a non-oxygenated environment, a typical example being underwater keel bolts buried in timber. When stainless steel parts such as nuts and bolts are forced together, when forcibly disassembled, the welded material may be torn and pitted, a destructive effect known as galling. Galling can be avoided by the use of materials for the parts forced together, for example bronze and stainless steel. However, two different alloys electrically connected in a humid, even mildly acidic environment may act as a voltaic pile, nitronic alloys, made by selective alloying with manganese and nitrogen, may have a reduced tendency to gall. Additionally, threaded joints may be lubricated to provide a film between the two parts and prevent galling, low-temperature carburizing is another option that virtually eliminates galling and allows the use of similar materials without the risk of corrosion and the need for lubrication
34.
Aesthetics
–
Aesthetics is a branch of philosophy that explores the nature of art, beauty, and taste, with the creation and appreciation of beauty. It is more defined as the study of sensory or sensori-emotional values, sometimes called judgements of sentiment. More broadly, scholars in the field define aesthetics as critical reflection on art, in modern English, the term aesthetic can also refer to a set of principles underlying the works of a particular art movement or theory, one speaks, for example, of the Cubist aesthetic. The word aesthetic is derived from the Greek αἰσθητικός, which in turn was derived from αἰσθάνομαι, for some, aesthetics is considered a synonym for the philosophy of art since Hegel, while others insist that there is a significant distinction between these closely related fields. In practice, aesthetic judgement refers to the sensory contemplation or appreciation of an object, philosophical aesthetics has not only to speak about art and to produce judgments about art works, but has also to give a definition of what art is. Art is an entity for philosophy, because art deals with the senses. Hence, there are two different conceptions of art in aesthetics, art as knowledge or art as action, any aesthetic doctrines that guided the production and interpretation of prehistoric art are mostly unknown. Western aesthetics usually refers to Greek philosophers as the earliest source of aesthetic considerations. Plato believed in beauty as a form in which beautiful objects partake and he felt that beautiful objects incorporated proportion, harmony, and unity among their parts. Similarly, in the Metaphysics, Aristotle found that the elements of beauty were order, symmetry. From the late 17th to the early 20th century Western aesthetics underwent a revolution into what is often called modernism. German and British thinkers emphasized beauty as the key component of art and of the aesthetic experience, and saw art as necessarily aiming at absolute beauty. For Alexander Gottlieb Baumgarten aesthetics is the science of the experiences, a younger sister of logic. For Immanuel Kant the aesthetic experience of beauty is a judgment of a subjective but similar human truth, however, beauty cannot be reduced to any more basic set of features. For Friedrich Schiller aesthetic appreciation of beauty is the most perfect reconciliation of the sensual and rational parts of human nature, for Friedrich Wilhelm Joseph Schelling, the philosophy of art is the organon of philosophy concerning the relation between man and nature. So aesthetics began now to be the name for the philosophy of art, Friedrich von Schlegel, August Wilhelm Schlegel, Friedrich Schleiermacher and Georg Wilhelm Friedrich Hegel also gave lectures on aesthetics as philosophy of art after 1800. For Hegel, all culture is a matter of absolute spirit coming to be manifest to itself, stage by stage, Art is the first stage in which the absolute spirit is manifest immediately to sense-perception, and is thus an objective rather than subjective revelation of beauty. It is thus for Schopenhauer one way to fight the suffering, the British were largely divided into intuitionist and analytic camps
35.
Vikings
–
The term is also commonly extended in modern English and other vernaculars to the inhabitants of Viking home communities during what has become known as the Viking Age. Facilitated by advanced seafaring skills, and characterised by the longship, Viking activities at times also extended into the Mediterranean littoral, North Africa, the Middle East and Central Asia. A romanticized picture of Vikings as noble savages began to emerge in the 18th century, current popular representations of the Vikings are typically based on cultural clichés and stereotypes, complicating modern appreciation of the Viking legacy. One etymology derives víking from the feminine vík, meaning creek, inlet, various theories have been offered that the word viking may be derived from the name of the historical Norwegian district of Viken, meaning a person from Viken. According to this theory, the word simply described persons from this area, however, there are a few major problems with this theory. People from the Viken area were not called Viking in Old Norse manuscripts, in addition, that explanation could only explain the masculine and ignore the feminine, which is a serious problem because the masculine is easily derived from the feminine but hardly vice versa. The form also occurs as a name on some Swedish rune stones. There is little indication of any negative connotation in the term before the end of the Viking Age and this is found in the Proto-Nordic verb *wikan, ‘to turn’, similar to Old Icelandic víkja ‘to move, to turn’, with well-attested nautical usages. In that case, the idea behind it seems to be that the rower moves aside for the rested rower on the thwart when he relieves him. A víkingr would then originally have been a participant on a sea journey characterized by the shifting of rowers, in that case, the word Viking was not originally connected to Scandinavian seafarers but assumed this meaning when the Scandinavians begun to dominate the seas. In Old English, the word wicing appears first in the Anglo-Saxon poem, Widsith, in Old English, and in the history of the archbishops of Hamburg-Bremen written by Adam of Bremen in about 1070, the term generally referred to Scandinavian pirates or raiders. As in the Old Norse usages, the term is not employed as a name for any people or culture in general, the word does not occur in any preserved Middle English texts. The Vikings were known as Ascomanni ashmen by the Germans for the ash wood of their boats, Lochlannach by the Gaels, the modern day name for Sweden in several neighbouring countries is possibly derived from rōþs-, Ruotsi in Finnish and Rootsi in Estonian. The Slavs and the Byzantines also called them Varangians, Scandinavian bodyguards of the Byzantine emperors were known as the Varangian Guard. The Franks normally called them Northmen or Danes, while for the English they were known as Danes or heathen. It is used in distinction from Anglo-Saxon, similar terms exist for other areas, such as Hiberno-Norse for Ireland and Scotland. The period from the earliest recorded raids in the 790s until the Norman conquest of England in 1066 is commonly known as the Viking Age of Scandinavian history, Vikings used the Norwegian Sea and Baltic Sea for sea routes to the south. The Normans were descended from Vikings who were given feudal overlordship of areas in northern France—the Duchy of Normandy—in the 10th century, in that respect, descendants of the Vikings continued to have an influence in northern Europe
36.
Chevron (insignia)
–
A chevron is an inverted V-shaped pattern. The chevron occurs in early art including designs on pottery and rock carvings, examples can be found approximately 1800 BC in archaeological recovery of pottery designs from the palace of Knossos on Crete in the modern day country of Greece. Sparta used a capital lambda on their shields, a chevron is one of the ordinaries in heraldry, one of the simple geometrical figures which are the chief images in many coat of arms. It can be subject to a number of modifications, when the ends are cut off in a way that looks like the splintered ends of a broken piece of wood, with an irregular zig-zag pattern, it is called éclaté. When shown as a smaller size than standard, it is a called a chevronel. Chevrons appeared early in the history of heraldry, especially in Normandy, in Scandinavia the chevron is known as sparre, an early example appears in the arms of Armand desmondly. In areas observing Commonwealth of Nations or United States doctrine, chevrons are used as an insignia of enlisted or NCO rank by military forces, one chevron usually designates a lance corporal, two a corporal, and three a sergeant. One to four rockers may also be incorporated to indicate various grades of sergeant, in American usage, chevrons typically point towards the neck, in Commonwealth usage they usually point away from the neck. In the Commonwealth, the terminology for rank chevrons includes the number of stripes, called bars, therefore. Canadian and Australian Forces often refer to chevrons as hooks, in the Dutch armed forces they are nicknamed bananas. In some armies, small chevrons are worn on the left sleeve to indicate length of service. The Israel Defense Forces use chevrons in various orientations as organizational designators on their vehicles, specifically which company within a battalion they belong to
37.
Chainsaw
–
A chainsaw is a portable, mechanical saw which cuts with a set of teeth attached to a rotating chain that runs along a guide bar. It is used in such as tree felling, limbing, bucking, pruning, cutting firebreaks in wildland fire suppression. Chainsaws with specially designed bar and chain combinations have been developed as tools for use in chainsaw art, specialized chainsaws are used for cutting concrete. Chainsaws are sometimes used for cutting ice, for example for ice sculpture, someone who uses a saw is a sawyer. The origin is debated, but a tool was made around 1830 by the German orthopaedist Bernhard Heine. This instrument, the osteotome, had links of a chain carrying small cutting teeth with the set at an angle. As the name implies, this was used to cut bone, the chain hand saw, a fine serrated link chain which cut on the concave side, was invented around 1783-1785. It was illustrated in Aitkens Principles of Midwifery or Puerperal Medicine, Jeffray claimed to have conceived the idea of the chain saw independently about that time but it was 1790 before he was able to have it produced. In 1806, Jeffray published Cases of the Excision of Carious Joints by H. Park, in this communication he translated Moreaus paper of 1803. Park and Moreau described successful excision of diseased joints, particularly the knee, Jeffray explained that the chain saw would allow a smaller wound and protect the adjacent neurovascular bundle. While a heroic concept, symphysiotomy had too many complications for most obstetricians but Jeffrays ideas became accepted, mechanised versions of the chain saw were developed but in the later 19th Century, it was superseded in surgery by the Gigli twisted wire saw. For much of the 19th century, however, the saw was a useful surgical instrument. The earliest patent for an endless chain saw was granted to Samuel J. Bens of San Francisco on January 17,1905. His intent being to fell giant redwoods, the first portable chainsaw was developed and patented in 1918 by Canadian millwright James Shand. After he allowed his rights to lapse in 1930 his invention was developed by what became the German company Festo in 1933. The company now operates as Festool producing portable power tools, in 1927, Emil Lerp, the founder of Dolmar, developed the worlds first gasoline-powered chainsaw and mass-produced them. World War II interrupted the supply of German chain saws to North America, so new manufacturers sprang up including Industrial Engineering Ltd in 1947, Ltd and part of Outboard Marine Corporation, the oldest manufacturer of chainsaws in North America. McCulloch in North America started to produce chainsaws in 1948, the early models were heavy, two-person devices with long bars
38.
Mosaic
–
A mosaic is a piece of art or image made from the assemblage of small pieces of colored glass, stone, or other materials. It is often used in art or as interior decoration. Most mosaics are made of small, flat, roughly square, pieces of stone or glass of different colors, some, especially floor mosaics, are made of small rounded pieces of stone, and called pebble mosaics. Others are made of other materials, mosaics have a long history, starting in Mesopotamia in the 3rd millennium BC. Pebble mosaics were made in Tiryns in Mycenean Greece, mosaics with patterns and pictures became widespread in classical times, Early Christian basilicas from the 4th century onwards were decorated with wall and ceiling mosaics. Mosaic fell out of fashion in the Renaissance, though artists like Raphael continued to practise the old technique, Roman and Byzantine influence led Jews to decorate 5th and 6th century synagogues in the Middle East with floor mosaics. Mosaic was widely used on buildings and palaces in early Islamic art, including Islams first great religious building, the Dome of the Rock in Jerusalem. Mosaic went out of fashion in the Islamic world after the 8th century, modern mosaics are made by professional artists, street artists, and as a popular craft. Many materials other than stone and ceramic tesserae may be employed, including shells, glass. The earliest known examples of made of different materials were found at a temple building in Abra, Mesopotamia. They consist of pieces of colored stones, shells and ivory, excavations at Susa and Chogha Zanbil show evidence of the first glazed tiles, dating from around 1500 BC. However, mosaic patterns were not used until the times of Sassanid Empire, mythological subjects, or scenes of hunting or other pursuits of the wealthy, were popular as the centrepieces of a larger geometric design, with strongly emphasized borders. Pliny the Elder mentions the artist Sosus of Pergamon by name, describing his mosaics of the left on a floor after a feast. Both of these themes were widely copied, most recorded names of Roman mosaic workers are Greek, suggesting they dominated high quality work across the empire, no doubt most ordinary craftsmen were slaves. Splendid mosaic floors are found in Roman villas across North Africa, in such as Carthage. The tiny tesserae allowed very fine detail, and an approach to the illusionism of painting, often small panels called emblemata were inserted into walls or as the highlights of larger floor-mosaics in coarser work. The normal technique was opus tessellatum, using larger tesserae, which was laid on site, there was a distinct native Italian style using black on a white background, which was no doubt cheaper than fully coloured work. In Rome, Nero and his architects used mosaics to cover surfaces of walls and ceilings in the Domus Aurea, built 64 AD
39.
Powder metallurgy
–
Powder metallurgy is a term covering a wide range of ways in which materials or components are made from metal powders. PM processes can avoid, or greatly reduce, the need to use metal removal processes, thereby drastically reducing yield losses in manufacture, Powder metallurgy is also used to make unique materials impossible to get from melting or forming in other ways. A very important product of this type is tungsten carbide, WC is used to cut and form other metals and is made from WC particles bonded with cobalt. It is very used in industry for tools of many types and globally ~50. Other products include sintered filters, porous oil-impregnated bearings, electrical contacts, the PM press and sinter process generally consists of three basic steps, powder blending, die compaction, and sintering. Optional secondary processing such as coining or heat treatment often follows to obtain special properties or enhanced precision and this produces precise parts, normally very close to the die dimensions, but with 5-15% porosity, and thus sub-wrought steel properties. There are several other PM processes which have developed over the last fifty years. A preform made by the press and sinter method is heated and then hot forged to full density. Here the powder is filled into a mould, normally consisting of a metallic can of suitable shape, the can is vibrated, then evacuated and sealed. It is then placed in a hot press, where it is heated to a homologous temperature of around 0.7. This results in a part of full density with as-wrought or better. HIP was invented in the 1950-60s and entered production in the 1970-80s. In 2015, it was used to produce ~25, 000t/yr of stainless and tool steels and this part is then heated or otherwise treated to remove the binder to give a brown part. This part is then sintered, and shrinks by ~18% to give a complex, invented in the 1970s, production has increased since 2000 with an estimated global volume in 2014 of 12, 000t worth €1265millions. Powders employed in ECAS can avoid binders thanks to the possibility of direct sintering, without the need of pre-pressing, the most common of these technologies is hot pressing, which has been under use for the production of the diamond tools employed in the construction industry. Spark plasma sintering and electro sinter forging are two modern, industrial commercial ECAS technologies, additive manufacturing is a relatively novel family of techniques which use metal powders to make parts by laser sintering or melting. This is a process under development as of 2015. Sintering involves the production of a solid metal or ceramic piece from a starting powder
40.
Bluing (steel)
–
Bluing is a passivation process in which steel is partially protected against rust, and is named after the blue-black appearance of the resulting protective finish. True gun bluing is a conversion coating resulting from an oxidizing chemical reaction with iron on the surface selectively forming magnetite. Black oxide provides minimal protection against corrosion, unless treated with a water-displacing oil to reduce wetting. A distinction can be made between traditional bluing and some more modern black oxide coatings, although bluing is a subset of black oxide coatings. In comparison, rust, the red oxide of iron, undergoes a large volume change upon hydration, as a result. Cold, Hot, Rust Blue and Fume Blue are oxidizing processes simply referred to as bluing, cold bluing is generally a selenium dioxide based compound that colours steel black, or more often a very dark grey. It is a product to apply evenly, offers minimal protection and is generally best used for small fast repair jobs. The Hot process is a salt solution, referred to as Traditional Caustic Black. This method was adopted by larger companies for large scale. It does provide good rust resistance which is improved with the use of oil, Rust Bluing and Fume Bluing provide the best rust and corrosion resistance as the process continually converts any metal that is capable of rusting into magnetite. Treating with an oiled coating enhances the protection offered by the bluing and this process is also the only process safely used to re-blue vintage shotguns. Many double barrelled shotguns are soft soldered / silver brazed together, the higher temperatures of the other processes as well as their caustic nature will weaken the soldered joints and make the gun hazardous to use. Bluing can also be done in a furnace, for example for a sword or other item traditionally made by a blacksmith or specialist such as a weaponsmith. Blacksmith products to this day may occasionally be made from blued steel by traditional craftsmen in cultures. Bluing is most commonly used by gun manufacturers, gunsmiths, and gun owners to improve the appearance of. It was also used by machinists, who protected and beautified tools made for their own use, Bluing also helps to maintain the metal finish by resisting superficial scratching, and also helps to reduce glare to the eyes of the shooter when looking down the barrel of the gun. All blued parts still need to be oiled to prevent rust. Bluing, being a conversion coating, is not as robust against wear and corrosion resistance as plated coatings
41.
Electrical discharge machining
–
Material is removed from the workpiece by a series of rapidly recurring current discharges between two electrodes, separated by a dielectric liquid and subject to an electric voltage. One of the electrodes is called the tool-electrode, or simply the tool or electrode, while the other is called the workpiece-electrode, the process depends upon the tool and workpiece not making actual contact. This phenomenon is the same as the breakdown of a capacitor, as a result, material is removed from the electrodes. Adding new liquid dielectric in the volume is commonly referred to as flushing. Also, after a current flow, the difference of potential between the electrodes is restored to what it was before the breakdown, so that a new liquid dielectric breakdown can occur, the erosive effect of electrical discharges was first noted in 1770 by English physicist Joseph Priestley. Two Russian scientists, B. R. Butinzky and N. I, lazarenko, were tasked in 1943 to investigate ways of preventing the erosion of tungsten electrical contacts due to sparking. They failed in this task but found that the erosion was more precisely controlled if the electrodes were immersed in a dielectric fluid and this led them to invent an EDM machine used for working difficult-to-machine materials such as tungsten. The Lazarenkos machine is known as an R-C-type machine, after the circuit used to charge the electrodes. Simultaneously but independently, an American team, Harold Stark, Victor Harding, initially constructing their machines from feeble electric-etching tools, they were not very successful. But more powerful sparking units, combined with automatic spark repetition, Stark, Harding, and Beavers machines were able to produce 60 sparks per second. Later machines based on their design used vacuum tube circuits that were able to produce thousands of sparks per second, the wire-cut type of machine arose in the 1960s for the purpose of making tools from hardened steel. The tool electrode in wire EDM is simply a wire, to avoid the erosion of material from the wire causing it to break, the wire is wound between two spools so that the active part of the wire is constantly changing. The earliest numerical controlled machines were conversions of punched-tape vertical milling machines, the first commercially available NC machine built as a wire-cut EDM machine was manufactured in the USSR in 1967. Machines that could optically follow lines on a master drawing were developed by David H. Dulebohns group in the 1960s at Andrew Engineering Company for milling and grinding machines, master drawings were later produced by computer numerical controlled plotters for greater accuracy. A wire-cut EDM machine using the CNC drawing plotter and optical line follower techniques was produced in 1974, dulebohn later used the same plotter CNC program to directly control the EDM machine, and the first CNC EDM machine was produced in 1976. Electrical discharge machining is a machining method primarily used for hard metals or those that would be difficult to machine with traditional techniques. EDM typically works with materials that are conductive, although methods for machining insulating ceramics with EDM have also been proposed. EDM can cut intricate contours or cavities in pre-hardened steel without the need for treatment to soften and re-harden them
42.
Medieval period
–
In the history of Europe, the Middle Ages or Medieval Period lasted from the 5th to the 15th century. It began with the fall of the Western Roman Empire and merged into the Renaissance, the Middle Ages is the middle period of the three traditional divisions of Western history, classical antiquity, the medieval period, and the modern period. The medieval period is subdivided into the Early, High. Population decline, counterurbanisation, invasion, and movement of peoples, the large-scale movements of the Migration Period, including various Germanic peoples, formed new kingdoms in what remained of the Western Roman Empire. In the seventh century, North Africa and the Middle East—once part of the Byzantine Empire—came under the rule of the Umayyad Caliphate, although there were substantial changes in society and political structures, the break with classical antiquity was not complete. The still-sizeable Byzantine Empire survived in the east and remained a major power, the empires law code, the Corpus Juris Civilis or Code of Justinian, was rediscovered in Northern Italy in 1070 and became widely admired later in the Middle Ages. In the West, most kingdoms incorporated the few extant Roman institutions, monasteries were founded as campaigns to Christianise pagan Europe continued. The Franks, under the Carolingian dynasty, briefly established the Carolingian Empire during the later 8th, the Crusades, first preached in 1095, were military attempts by Western European Christians to regain control of the Holy Land from Muslims. Kings became the heads of centralised nation states, reducing crime and violence, intellectual life was marked by scholasticism, a philosophy that emphasised joining faith to reason, and by the founding of universities. Controversy, heresy, and the Western Schism within the Catholic Church paralleled the conflict, civil strife. Cultural and technological developments transformed European society, concluding the Late Middle Ages, the Middle Ages is one of the three major periods in the most enduring scheme for analysing European history, classical civilisation, or Antiquity, the Middle Ages, and the Modern Period. Medieval writers divided history into periods such as the Six Ages or the Four Empires, when referring to their own times, they spoke of them as being modern. In the 1330s, the humanist and poet Petrarch referred to pre-Christian times as antiqua, leonardo Bruni was the first historian to use tripartite periodisation in his History of the Florentine People. Bruni and later argued that Italy had recovered since Petrarchs time. The Middle Ages first appears in Latin in 1469 as media tempestas or middle season, in early usage, there were many variants, including medium aevum, or middle age, first recorded in 1604, and media saecula, or middle ages, first recorded in 1625. The alternative term medieval derives from medium aevum, tripartite periodisation became standard after the German 17th-century historian Christoph Cellarius divided history into three periods, Ancient, Medieval, and Modern. The most commonly given starting point for the Middle Ages is 476, for Europe as a whole,1500 is often considered to be the end of the Middle Ages, but there is no universally agreed upon end date. English historians often use the Battle of Bosworth Field in 1485 to mark the end of the period
43.
Wootz steel
–
It is the pioneering steel alloy matrix developed in Southern India in the 6th century BC and exported globally. It was also known in the ancient world by different names including Wootz, Ukku, Hindvi Steel, Hinduwani Steel, Teling Steel. There are several ancient Tamil, Greek, Chinese and Roman literary references to high carbon Indian steel since the time of Alexanders India campaign. e, Seric Iron to the Romans, Egyptians, Chinese and Arabs by 500 BC. The steel was exported as cakes of steely iron that came to be known as Wootz, the Tamilakam method was to heat black magnetite ore in the presence of carbon in a sealed clay crucible inside a charcoal furnace. An alternative was to smelt the ore first to give wrought iron, the carbon source was bamboo and leaves from plants such as Avārai. The Chinese and locals in Sri Lanka adopted the methods of creating wootz steel from the Chera Tamils by the 5th century BC. In Sri Lanka, this early steel-making method employed a unique wind furnace, production sites from antiquity have emerged, in places such as Anuradhapura, Tissamaharama and Samanalawewa, as well as imported artifacts of ancient iron and steel from Kodumanal. The Arabs introduced the South Indian/Sri Lankan wootz steel to Damascus, the 12th century Arab traveler Edrisi mentioned the Hinduwani or Indian steel as the best in the world. Another sign of its reputation is seen in a Persian phrase – to give an Indian answer, Wootz steel was widely exported and traded throughout ancient Europe and the Arab world, and became particularly famous in the Middle East. From the 17th century onwards, several European travelers observed the manufacturing in South India, at Mysore, Malabar. The word wootz appears to have originated as a mistranscription of wook, a version of ukku. According to one theory, the word ukku is based on the melt, dissolve. The Tamil language root word for the alloy is urukku, another theory says that the word is a variation of uchcha or ucha. When Benjamin Heyne inspected the Indian steel in Ceded Districts and other Kannada-speaking areas, he was informed that the steel was ucha kabbina, legends of wootz steel and Damascus swords aroused the curiosity of the European scientific community from the 17th to the 19th century. The use of alloys was not known in Europe previously and thus the research into wootz steel played an important role in the development of modern English, French. In 1790, samples of wootz steel were received by Sir Joseph Banks, president of the British Royal Society and these samples were subjected to scientific examination and analysis by several experts. Specimens of daggers and other weapons were sent by the Rajahs of India to the The Great Exhibition in London in 1851 and 1862 International Exhibition, though the arms of the swords were beautifully decorated and jeweled, they were most highly prized for the quality of their steel. The swords of the Sikhs were said to bear bending and crumpling, Wootz is characterized by a pattern caused by bands of clustered Fe 3C particles made of microsegregation of low levels of carbide-forming elements
44.
Russia
–
Russia, also officially the Russian Federation, is a country in Eurasia. The European western part of the country is more populated and urbanised than the eastern. Russias capital Moscow is one of the largest cities in the world, other urban centers include Saint Petersburg, Novosibirsk, Yekaterinburg, Nizhny Novgorod. Extending across the entirety of Northern Asia and much of Eastern Europe, Russia spans eleven time zones and incorporates a range of environments. It shares maritime borders with Japan by the Sea of Okhotsk, the East Slavs emerged as a recognizable group in Europe between the 3rd and 8th centuries AD. Founded and ruled by a Varangian warrior elite and their descendants, in 988 it adopted Orthodox Christianity from the Byzantine Empire, beginning the synthesis of Byzantine and Slavic cultures that defined Russian culture for the next millennium. Rus ultimately disintegrated into a number of states, most of the Rus lands were overrun by the Mongol invasion. The Soviet Union played a role in the Allied victory in World War II. The Soviet era saw some of the most significant technological achievements of the 20th century, including the worlds first human-made satellite and the launching of the first humans in space. By the end of 1990, the Soviet Union had the second largest economy, largest standing military in the world. It is governed as a federal semi-presidential republic, the Russian economy ranks as the twelfth largest by nominal GDP and sixth largest by purchasing power parity in 2015. Russias extensive mineral and energy resources are the largest such reserves in the world, making it one of the producers of oil. The country is one of the five recognized nuclear weapons states and possesses the largest stockpile of weapons of mass destruction, Russia is a great power as well as a regional power and has been characterised as a potential superpower. The name Russia is derived from Rus, a state populated mostly by the East Slavs. However, this name became more prominent in the later history, and the country typically was called by its inhabitants Русская Земля. In order to distinguish this state from other states derived from it, it is denoted as Kievan Rus by modern historiography, an old Latin version of the name Rus was Ruthenia, mostly applied to the western and southern regions of Rus that were adjacent to Catholic Europe. The current name of the country, Россия, comes from the Byzantine Greek designation of the Kievan Rus, the standard way to refer to citizens of Russia is Russians in English and rossiyane in Russian. There are two Russian words which are translated into English as Russians
45.
Japanese swordsmithing
–
Japanese sword blades were often forged with different profiles, different blade thicknesses, and varying amounts of grind. Wakizashi and tantō were not simply scaled-down katana, they were often forged without ridge or other forms which were very rare on katana. The steel used is known as tamahagane, or jewel steel, tamahagane is produced from iron sand, a source of iron ore, and mainly used to make Samurai swords, such as the katana, and some tools. The smelting process used is different from the mass production of steel. A clay vessel about 1.1 m tall,3 m long and this is known as a tatara. After the clay tub has set, it is fired until dry, a charcoal fire is started from soft pine charcoal. Then the smelter will wait for the fire to reach the correct temperature, at that point he will direct the addition of iron sand known as satetsu. This will be layered in with more charcoal and more iron sand over the next 72 hours, four or five people need to constantly work on this process. It takes about a week to build the tatara and complete the conversion to steel. Because the charcoal cannot exceed the point of iron, the steel is not able to become fully molten. When complete, the Tatara is broken to remove the steel bloom, a single kera can typically be worth hundreds of thousands of dollars, making it many times more expensive than modern steels. The swordsmiths will carefully break the kera apart, and separate the various carbon steels, the lowest carbon steel is called hocho-tetsu, which is used for the shingane of the blade. The most useful process is the folding, where the metals are welded, folded. The folding removes impurities and helps out the carbon content. Currently, tamahagane is only three or four times a year by Nittoho and Hitachi Metals during winter in a wood building and is only sold to the master swordsmiths to use once it is made. The forging of a Japanese blade typically took many days or weeks, as with many complex endeavors, rather than a single craftsman, several artists were involved. There was a smith to forge the rough shape, often a second smith to fold the metal, a specialist polisher, often, there were sheath, hilt, and handguard specialists as well. The steel bloom, or kera, that is produced in the tatara contains steel that varies greatly in carbon content, three types of steel are chosen for the blade, a very low carbon steel called hocho-tetsu is used for the core of the blade
46.
Mokume-gane
–
Mokume-gane is a Japanese metalworking procedure which produces a mixed-metal laminate with distinctive layered patterns. Mokume gane translates closely to wood grain metal or wood eye metal, Mokume-gane has been used to create many artistic objects. Though the technique was first created to decorate swords, the art survives mostly in the form of jewelry. Mokume-gane is a made by fusing several layers of different coloured precious metals together to form a sandwich of alloys called a billet. The billet is then manipulated in such a way that a pattern resembling wood grain emerges over the surface, there are many ways of working the mokume metal to create different patterns. Once the metal has been rolled in to sheet metal or bar, first made in 17th-century Japan, mokume-gane was used only for swords. As the traditional samurai sword stopped serving as a weapon and became largely a status symbol, to meet this demand, Denbei Shoami, a master metalworker from Akita prefecture, first came up with the process for creating mokume-gane. He initially called his product guri bori for its simplest forms resemblance to guri, other historical names for it were kasumi-uchi, itame-gane, and yosefuki. The traditional components were relatively soft metallic elements and alloys which would form liquid phase diffusion bonds with one another without completely melting and this was useful in the traditional techniques of fusing and soldering the layers together. Over time, the practice of making mokume-gane faded, the katana industry dried up in the late 1800s when the traditional caste system dissolved and people were no longer able to carry their swords in public. The few metalsmiths who practiced in mokume transferred their skills to other objects. Tiffany & Co. s silver division under the direction of Edward C, tiffanys display again won the grand prize for silver wares, and the company continued to produce its Japanesque silver with mokume up into the twentieth century. By the twentieth century, mokume-gane was almost entirely unknown, japan’s movement away from traditional craftwork, paired with the great difficulty of mastering the mokume-gane art had brought mokume artisans to the brink of extinction. It reached a point where only scholars and collectors of metalwork were aware of the technique and it was not until the 1970s, when Eugene Michael Pijanowski and Hiroko Sato Pijanowski brought mokume works to the United States, that the artform re-emerged in the public eye. Today, jewelry, flatware, hollowware, spinning tops and other objects are made using this material. Modern processes are controlled and include a compressive force on the billet. Metal sheets were stacked and carefully heated, the billet of simple stripes could be forged and carved to increase the patterns complexity. Successful lamination using the process requires a highly skilled smith with a great deal of experience
